Introduction Even the best solar PV systems can underperform or fail if not installed or maintained properly. From poor design choices to improper wiring, these issues can reduce efficiency, increase maintenance costs, or even pose safety risks. Here’s a guide to the most common issues we encounter—and how Moontree Solar avoids them.
1. Shadowing Without Optimisers A single shadowed panel on a string will reduce the performance of all panels connected to that string. If two panels are shadowed, one per string – then your entire solar generation will operate at a fraction of its capacity..often unknown hence often unresolved resulting in very poor generation and a very poor ROI.
- Solution: Install optimisers on any panel likely to experience shading.
- Best Practice: Conduct a shading analysis at the design stage. Design your system with minimum shadowing and if there is shadowing, always use an optimiser.
2. Poor DC Cabling Uusing undersized or incorrect Cabling will likely cause voltage drop and loss in performance, it might also be fire hazard and long-term efficiency losses.
- Minimum Standard: 4mm², preferably 6mm² for long runs
- Protection: Double insulation, plus conduit or trunking when exposed
3. Mismatched Panels & Inverters Incorrectly pairing panels with inverters results in suboptimal performance and ROI.
- Common Mistake: Under-sizing system with 16–18 panels when 24 are possible
- Impact: Slower ROI, higher long-term cost
4. Lack of Monitoring Without a proper meter or monitoring device, users can’t assess performance.
- Solution: Always install a CHINT meter or smart monitoring system
- Benefit: Real-time insights into generation, export, and usage
5. Poor System Programming Inverters not configured correctly for battery charge profiles or grid compliance can cause underperformance.
- Consequence: Battery underutilisation, grid feedback issues
- Solution: Ensure all systems are programmed by trained technicians
6. Roof Damage During Install Improper tools or techniques can lead to broken slates, leaks, and future structural issues.
- Problem:Lack of care during installation causing broken slates and tiles and not repairing.
- Prevention: Never ignore broken slates/tiles. Use registered and experienced solar contractors whom are local and accountable.
7. Fire Risk from Panel or Cable Damage Micro-cracks in panels (from walking on them) or loose DC connectors can lead to arcing and fires.
- Problem: Lack of care during installation walking across solar panels to access other areas of the roof.
- Prevention: Never, ever walk on solar panels. Walking on solar panels will unfortunately have little effect for the first couple of years, thereafter with each winter the Freeze/Thaw effect will enlargen the microcracks and lead to serious issue which can cause a fire
Fire Risk from poor cabling/connections..
- Problem: Poor or loose connections over time can ARC. This arcing creates carbon, the more it arcs, the more carbon created the worse the connection. Eventually this becomes impossible to transfer energy and when generation is high will arc around the connection issue and burn the cable in the process, leading to fire.
- Prevention: Fitting connectors is not hard, but needs to be done by capable engineers to ensure it is done correctly and ensure that this risk is eliminated. This is the single biggest issue within the solar industry – poor connection caused by ill-fitting cheaper connectors or badly fitted.
8. Battery & Inverter Compatibility Issues Using incompatible battery brands with inverters leads to faults or tripping.
- Dangerous Fix: Some installers remove earthing to avoid tripping—this is a serious safety risk!
- Our Solution: Only use certified combinations with full integration support
9. Inadequate System Sizing Under-sizing a system can make ROI unachievable and leave users disappointed.
- Mistake: Fitting systems with too few panels or poor orientation
- Recommendation: Prioritise max panel count before batteries if on a budget
10. Poor Fireproofing Shunts, batteries, and inverters need fire protection in timber or plasterboard environments.
- Neglect: Some systems are fitted directly to combustible walls
- Compliance: Use fireback board or install on non-combustible surfaces
11. Cable Chafing or Water Ingress Loose cables can rub and wear, causing arcing or high-resistance faults over time.
- Capillary Effect: Moisture drawn into cables over time causes corrosion
- Solution: All cables should be secured neatly to avoid chafing and exposure. Use lids when possible or trunking to protect cables
Conclusion Installing a solar PV system is not just about putting panels on a roof—it requires precise design, high standards, and experience. Moontree Solar delivers every installation with these risks in mind, ensuring safety, reliability, and performance for years to come.
If you’d like a system designed the right way—reach out to our team today.
